9. I would put money

that it is a BB from a higher powered air gun or a pellet at a lesser power.

The damage appears identical to what a local store received some years back:

-Small center hole
-Rounded divot on interior, approximately quarter-sized diameter
-Entire window breaks but remains intact (if it breaks at all)
-no signs of damage to interior from projectile. (the bb/pellet actually bounced off and is outside the building)